Removable coating for photographic film



Aug. 13, 1940. G. F. NADEAU ET AL REMOVABLE COATING FOR PHOTOGRAPHIC FILM Filed May 12. 1939 MUL/ON LAYER.

%Oj ?ZO? x ANTI -h'A/.A T/ON LA YER OF /2\ w CELLULOSE ACETATE PHTHALATE. [3 DVE LAYER CONTAN//Y ANESTER OFA saz/:Ho AL/PHAT/C D/CARBOXYL/C AC/D.

OVERCOA T/NG LAYER OF %TER-GOL UBLE /4 CEZL ULOSE ESTER OR PES/N CON TA /N/N 6 ?r ASALT OFAJULPHOSUCC//Y/C ESTER.

6445 Emma/;U

ALFREO D. ZACK INVENTOR BYyM A TTORNE YS Patented Aug. 13, 1940 UNITED s''aTEs 2,2 ,34s REMOVABLE coArmG Fon. ruoToGaArmo Gale F. Nadeau and Alfred D. Slack, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation .of New Jersey Application May 12, 1939, Serial No. ?13,298

11 Claims.

This invention relates to photographic film andparticularly to film havingovercoating or hacking layers removable in photographic baths.

The desirability of anti-halation layers or over-' coating layers for photographic films and plates` is well' known. It is also known that some of these materials are 'sometimes difllcult to remove due to lack of solubility of on'e or more of the backing or overcoating constituents in the regular processing baths or to the actual repellancy of the aqueous solutions by one or more of the constituents of the hacking or overcoating layer. An example of this is an anti-halation hacking which is applied to the film base or plate as a material which swells or dissolves in 'regular developing solutions, followed by an overcoating of a water-insoluble dyestuif or coloring material. When immersed in the developing baths, the first applied layer is supposed to dissolve or wash away from the film or plate carrying the overcoated dye layer with it. If, however, this dye layer or the carrier itself is either slowly soluble or actually repellant to the developing solutions, removal may be either slow or incomplete, or in some extreme cases there may be no removal -at all.

It is, therefore, an object of the present invention to provide novel means for hacking or overcoating photographic films or plates. A further object is to provide a backing or an overcoating layer which is readily removable in photographic processing baths. A still further object is to provide a backing or overcoating layer having increased wettability by the processing solutions. A' still further object is to provide a hacking or overcoating layer containing a wetting agent which functions as a dispersing agent for the removed particles, so that they are dlspersed in the wash water or processing baths and are not removed in large pieces.

These objects are accomplished by incorporating in or over the backings or overcoatings certain materials which greatly increase the susceptibility of the backing or overcoating to the processing solutions. A material of this type consists of the water soluble salts of esters of sulfo aliphatic dicarboxylic acids.

In the accompanying drawing, Fig. 1 is an enlarged sectional view of a film having an antihalation hacking according to our invention, and Fig. 2 is an enlarged sectional view of a photographic film having an overcoating layer according to our invention.

In the practice of our invention a suitable amount of the wetting agent is applied to the overcoating or backing layer from a solvent solution, or in the case of an anti-halation layer, lt is convenient to apply it in the dye solution itself. The wetting agent may also be contained 'photographic films or plates.

in the backing or overcoating layer for the purpose of increasng the susceptibility of the layer to the processing baths. The amount of wetting agent used is determined by the degree of wettability desired, the compatibility of the particular wetting agent with the dye solution (in the case of an anti-halation hacking), and the degree to which the given weight of wetting agent will reduce the surface tension at the-interface of llquid and solid.

specific wetting agents which we have found suitable for this purpose are the water-soluble salts of esters of sulfo aliphatic dicarboxylic adds, such as the calcium or sodium salt of diamyl sulfosuccinate, sold under the trade name Aerosol AY and the sodium salt of dioctyl sulfosuccinate, sold under the trade name Aerosol OT. These materials are sold by the American Cyanamide and Chemical Corporation.

The material to which these wetting agents are applied may consist of any substance which is water-soluble, or' forms water-soluble salts in the developer, or which is susceptible to the processing baths ordinarily used in the treatment of suitable materials are as follows: Cellulose esters containing a free carboxyl group, such as cellulose acetate phthalate, cellulose acetate succinate, or cellulose acetate maleate, the preparation of which is described in Genung U. S. Patent 2,126,460

August 9, 1938; water soluble salts of these esters, such as the ammo'nium and the amine salts, some of which are described in Blanchard application Serial No. 222302, filed July 30, 1938 cellulose ethers, such as ethyl cellulose phthalate, 'described in Genung U. S. Patent 2,126,460; polyvlnyl phthalate, described in Nadeau U. S. Patent 2,13l,747, October 4, 1938; polyvinyl alcohol, described in Sheppard et al., U. S. Patent 1,768,795, July 1, 1930; agar phthalate, described in Malm et al. application SerialNo. 230504, filed September 17, 1938; and others.

The following specific examples, which are illustrative only, will serve to illustrate our invention.

Example I Grams Cellulose acetate phthalate 8 Acetone 70 Methyl alcohol 22 This coating is dried down to form a continuous layer on the film and is then dyed with a solution of Spirit nigrosine NB containing the sodium salt or diamyl sulphosuccinate and having the following composition:

Gram: Spirit nigrosine NB 5 Methyl alcohol 88 Buty nlrnhnl 10 .Sodlum salt of dianyl sulphosuccinate 3 A photographic emulsion layer, after drying, is coated with a protective layer of polyvinyl phthalate containing a wetting agent and having the following composition:

Grams Polyvinyl phthalate 5 Methyl alcohol 46.5 Butyi acetate 46.5 Sodium salt or dioctyl sulphosuccinate 2 This layer is readily removable in the processing baths.

In the drawing accompanying this application, Flg. 1 shows a film support backed according to our invention. As shown therein, i. is a support of glass or suitable cellulosic material, such as cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or of a suitable synthetic resin, such as a polyvinyl acetaldehyde acetal resin. The support carries an emulsion layer ll and a backing layer I! consisting of cellulose acetate phthaiate. Over the backing layer l2 there is applied an anti-halation dye or pigment layer l3 containing a salt oi an ester of a sulpho aliphatic dicarboxylic acid. As shown in Fig. 2, the support o carries the emulsion layer ll and an overcoating layer ll oi a water-soluble or water-susceptible cellulose ester or synthetic resin containing a salt of an ester of a sulpho aliphatic dicarboxylic acid.

The specific wetting agents reierred to above are water soluble salts o! esters of sulio aliphatic dicarboxylic acid, or more specifically, esters o! aliphatic dibasic acids having the formula:

COOX coox where R is an aliphatic carbon chain containing at least one sulfonic acid group but no other substituent and X is a hydrogen atom or the radical of an alcohol containing not more than twelve carbon atoms or of a phenol not connected by a carbon to carbon bond to R, and at least one ot which X's is such alcohol or phenol radical. These compounds and methods ior preparing them are described in Jaeger U. S. Patent No. 2,028,091, January 4, 1936.

The aliphatic dicarboxylic acids used in the preparation of these compounds may be saturated or unsaturated and may comprise, for example, monoand di-sulfosuccinic acid, sultochlorsuccinic sulfoadipic acid, suliomaleic acid, suliopyrotarta-ic acid, sulfoglutaric acid, and other sulonated dicarboxylic acids of the aliphatic series. These acids may be esterified with a number oi diilferent alcohols such as methyl, ethyl, buty, amyl, hexyl and octyl. We prefer to use alcohols of not more than twelve carbon atoms since the wetting agents prepared with higher alcohols, although being good wetting agents, do not retain their water solubility. The water soluble salts of these esters are formed by reacting the sulionlc acid'group oi the ester with various bases such as sodium hydroxide, Organic amines. such aa methyl amine and tetraethanolamine, as well as other alkali bases.

In Staud U. S. 1,954,337, April 10, 1934, there is described a photographic film having an antihalation backing layer or an overcoating layer oi the acid form of cellulose acetate phthalate containing monoacetin for the purpose of increasing permeability of the coating. We have found, however, that the materials which we propose to use are superior to those described in the Staud patent. When using the wetting agents ot the present invention, the hacking layer is easily and readily removed and does not contaminate the developing solution or other bath in which the layer is removed. It is important, in processing photographic film, particularly motion picture fllm which is subjected to continuous treatment, that the hacking layer be removed as quickly and completely as possible. A material whichmakes possible this ready removal of the hacking is, thereiore, highly useful and is a desirable advance in the photographic art.

The materials and examples ot the present speciflcation are illustrative only and it is to be understood that numerous methods and ingredients may be used within the scope of the present description, and that our invention is to be taken as limited only by the scope oi the appended claims.

1. A sensitive photographic element comprising a superficial coating removable in photographic processing baths and in direct contact with said coating, a water soluble salt of an ester oi' a sulfo aliphatic dicarboxylic acid.

2. A sensitive photographic element comprising a superficial coating removable in photographic processing baths and in direct contact with said coating, a water soluble salt of an ester of an aliphatic dibasic acid having the formula COOX where R is an aliphatic carbon chain containing at least one sulfonic group but no other substituent, and X is selected from the group consisting of hydrogen alcohol of not more than twelve carbon atoms or phenol radicals not connected by a carbon to carbon bond to R, at least one X being such as alcohol or phenol radical.

3. A sensitive photographic element comprising a superficial coating containing as a wetting agent a water-soluble salt of an ester of a sulto aliphatic dicarboxylic acid and readily removable in photographic processing baths.

4. A sensitive photographic element comprising a water susceptible superficial coating and over said coating a layer containing a water soluble salt of an ester of a sulfo aliphatic dicarboxylic acid. the composite coating being readily removable in photographic processing baths.

5. A sensitive photographic element comprising a water susceptible superficial coating and over said coating a dye layer containing a water soluble salt of an ester of a sulfo aliphatic dicarboxylic acid, the composite coating being readily removable in photographic processing baths.

6. A sensitive photographic element comprising a supercial coating of cellulose acetate phthalate and over said coating a layer containing a water soluble salt of an ester oi a sulio aliphatic dicarboxylic acid, the composite coating being readily removable in photographic processing baths.

7. A sensitive photographic element comprising a hacking layer of cellulose acetate phthalate and over said layer a dye layer containing a water soluble salt of an ester of a sulfo aliphatic discarboxylic acid, the composite hacking being readily removable in photographic processing baths.

8. A sensitive photographic element comprising a superficial coating of a water susceptible material and over said coating a layer containing the water soluble salt of a sulfosuccinic ester, the composite coating being readily removable 15 in photographic processing baths.

9. A sensitive photographic element comprising a backing layer of a water susceptible material and over said layer a dye layer containing the sodium salt of an ester of sulfosuccinic acid, the composite hacking layer being readily removable in photographic processing baths.

10. A sensitive photographic element comprislng a supercial coating of cellulose acetate phthalate and over said coating a layer containing the sodium salt of diamylsulfosuccinate, the composite coating being readily removable in photographic processing baths.

11. A sensitive photographic element comprising a hacking layer of cellulose acetate phthalate and over said backing layer an anti-halation layer containing a coloring material and the sodium salt of diamylsulfcsuccinate.

GALE F. NADEAU. ALFRED D. SLACK. 

